So they erased a “good” general.
No, he was a bad general. He was fired by Lincoln and then ran against Lincoln during the war. He was a pompous ass. And he caused the war to go on much longer than it had to because he would never pursue the southern army as it was routed. Allowing Lee time to regroup and attack again. Lee’s artillery and cavalry were separated. All McClellan had to do was to take out the unprotected cannons and Lee would never have been able to mount a full out attack again.
“No, he was a bad general.”
Lincoln complained McCellan had the “case of the slows.”